Installation for the vaporisation, under vacuum, of the volatile constituent of an alloy



Jan. 9, 1962 M. CARON ETAL 3,016,237

INSTALLATION FOR THE VAPORISATION, UNDER VACUUM, OF THE VOLATILE CONSTITUENT OF AN ALLOY Filed Sept. 29, 1958 2 Sheets-Sheet 1 INVENTORS' MICHEL CARON GEORGES CHAUDRON LEON MOREAU Jan. 9, 1962 M. CARON ETAL 3,016,237

INSTALLATION FOR THE VAPORISATION, UNDER VACUUM, OF THE VOLATILE CONSTITUENT OF AN ALLOY 2 Sheets-Sheet 2 Filed Sept. 29, 1958 I III INVENTORS MICHEL CARON GEORGES CHAUDRON LEON MOREAU United States Patent 3,016,237 INSTALLATION FOR THE VAPORISATION, UN- DER VACUUM, OF THE VOLATILE CONSTITU- ENT OF AN ALLOY 1 Michel Caron, Sevres, Georges Chaudron, Paris, and Lon Moreau, Vitry, France, assignors to Commissariat a lEnergie Atomique, Paris, France Filed Sept. 29, 1958, Ser. No. 764,162 Claims priority, application France Oct. 9, 1957 7 Claims. (Cl. 26615) The present invention relates generally to the manufacture of porous membranes by evaporation, under vac- Y uurn, of the volatile constituent of an alloy, particularly the zinc of a brass or German silver.

More particularly, the invention relates to an installation comprising a furnace which is adapted to effect the treatment of bands, for instance of brass, to be dezincified, and in which a suitable temperature, of the order of 650 C., and a vacuum of the order of mm. of mercury, are maintained. This vacuum is obtained with the aid of a pump of which the output must be sufficient to permit the rapid evacuation of the zinc vapours in the vicinity of the band of brass. The furnace must cornprise regions which are cooled by a circulationof Water, where the zinc is deposited. v

- However, in an installation of this kind there is a risk on the one hand that the-zinc may recondense on the parts of the band of brass which have already been dezincified, and on the other hand that the vaporisation of the zinc may cause short-circuits in the heating furnace.

The present invention relates to a novel installation for the vaporisation, under vacuum, of the volatile constituent of an alloy, for instance the zinc of a band of brass or German silver, which will avoid the abovementioned disadvantages and permit the continuous manufacture of such bands.

An installation of this kind is essentially characterised in that it comprises in combination, disposed inside a vacuum chamber, a device for continuously unwinding the metal band to be treated, a furnace comprising two parallel heating surfaces between which the band moves, the temperature of the furnace increasing from the inlet to the outlet in the direction of advance of the band, and a tempering device disposed beyond the furnace and adapted to rapidly cool the metal band treated in the furnace.

Tempering can be effected for instance by passing the band between two copper-walls cooled by a current of water.

The vapours of the volatile constituent are evacuated from the furnace and are deposited on a system of condensers.

The resistances of the furnace are lators, for instance sheets of mica.

In a preferred embodiment of the invention, recondensation of the evaporated metal is avoided by producing two temperature gradients, one relatively small and increasing from the furnace inlet to the furnace outlet, and the other, decreasing rapidly, between the furnace outlet and the immediately adjacent region outside.

The metal band previously rolled and subjected to suitable heat treatments is wound on a first drum at the entry to the furnace; it then passes between two series of resistances; finally, it is wound onto a second drum at the outlet from the furnace. The tensile stress on the band is moderated.

The temperature of the furnace, which increases slightly (by about 10) from the furnace inlet to the furnace outlet, permits the first temperature gradient to be produced, whereby the recondensatio-n of the metal on the finished band is avoided.

protected by insu- 3,016,237 Patented Jan. 9, 1962 V furnace are protected by sheets of mica.

The following is a description, with reference to the accompanying drawings, of one embodiment, chosen by way of example and not of limitation, of an installation, constructed in accordance with the invention, for vaporisation under vacuum of the volatile constituent of an alloy.

In these drawings,

FIGURE 1 is a view, partly in section and partly in elevation, of a vacuum vaporisation installation constructed in accordance with the present invention, and

FIGURE 2 is a view in section on line II-II of FIGURE 1.

The drawings show only those elements which are necessary to enable the invention to be understood; corresponding elements carry the same reference numerals in both figures.

The dezincification installation shown in FIGURES l and 2 comprises, in a vacuum chamber 1, the furnace proper 2, the cooling system 3, and the zinc vapour condensation system 4.

The band of brass or German silver 5 to be dezincified is wound on a drum 6 before passing into the furnace 2, and is wound onto a drum 7 on emerging from the furnace 2 and after having been cooled at 3.

The band 5 passes between resistances 8 of the furnace 2. These resistances are protected by mica sheets 9.

The current for heating the resistances 8 passes for instance through wires 10 and gas-tight insulated passages 11.

Rapid cooling of the band on emerging from the furnace 2 through a slot in a refractory plate 12 is effected by a two-part refrigerating device 3; cooling water is supplied through a duct 13 and removed through a duct 14.

The furnace is provided with two apertures 15 and 16, one at the top and the other at the bottom, for the removal of the volatilised Zinc. The zinc vapour is directed by deflectors 17 and 18 onto vanes 19 of the condensation system '4 which are provided on the ducts 13 and 14 in these regions. The zinc that is not condensed on the vanes is removed through a duct 20 connected to a vacuum apparatus not shown in the drawings.

The furnace 2 and the drums 6 and 7 are mounted on a frame 21 rigid with the vacuum chamber. The tensile stress on the band is moderated.

The drums 6 and 7 are driven by arnotor 22. The drum 7 is driven directly by a shaft 23 and pinions 24 and 25, and the drum 6 is driven through the intermediary of pulleys 26 and 27, a belt 28, a shaft 29 and pinions 30 and 31. Rotary seals 32 and 33 prevent any leakage of gas around the shafts 23 and 29.

An observation window 34, made for instance of Pyrex glass, permits the operation of the furnace to be supervised.

What We claim is:

1. An installation for continuous vaporization, under vacuum, of the volatile constituent of a band made of a metal alloy, comprising in combination a chamber adapted to be evacuated, a furnace disposed inside the chamber and having a band inlet, a band outlet and two parallel interior surfaces defining opposite walls of a The metal is deposited on a that the temperature increases progressively fromthe band inlet to the band outlet, surfaces arranged laterally of the band and disposed in apertures in the furnace, means for cooling these laterally arranged surfaces, whereby a constituent of the band is volatilised in the furnace and condensed on said surfaces and a tempering device disposed inside the chamber but outside the furnace and adjacent to the band outlet and adapted to cool the band rapidly when the band emerges from the furnace.

2. An installation as claimed in claim 1, comprising electrical resistances adapted to heat the parallel surfaces, and sheets of insulating material disposed between said, resistances and said band adapted to protect the resistances.

3. An' installation as claimed in claim 1, which comprises a slotted plate made of a refractory material and closing the furnace at one end thereof and forming the band outlet, and in which the tempering'device comprises two copper walls adjacent to the plate, and ducts adapted to conduct water to and'from the copper Walls.

4. An. installation as claimed in claim 1, whereinsaid means disposed inside the chamber and adaptedtocontinuous'ly unwind a metal band and pass the hand through" 5 wound onto the drum adjacent to the band outlet.

5. An installation as claimed in claim 2, in which the insulating material is mica.

6.. Apparatus for treating a band of metallic alloy UNITED STATES PATENTS 1,337,465" Olson .Q. Apr; 20, 1920 1,646,498 Seede" Oct. 25, 1927 2,109,204 Wilsoni; Feb; 22, 1938 2,255,844 Gentil Sept." 16, 19 i 2,351,489f: Cooper June 13, 1944 2,351,937 Lynn' Ju'ne'=20,194'4' 2,367,617 Romavelli et a1. Jan. 16,1945

, 2,423,729 Ruhle July 8,1947

' 2,441,500 Miss May 11, 1948 2,890,878 Steinherz June 16, 1959 from that drum. and drawnthrough the turnace'and- 4. at least one constituent of which is a volatizable element, said apparatus comprising: a vacuum'chamber; a furnace mounted within said chamber and having an inlet and an outlet formed in opposed relation in the walls thereof; means in said chamber for holding said band, said band being fed therefrom through said furnace between said inlet and said outlet, said furnaceheing provided with heating means to raise the temperature of said band above the volatilization temperature of said vaporizable element to effect volatilization thereof; means communicating with the interior-of Said furnace at a point between said inlet and saidoutlet for removing a portion of the volatilized element therefrom; cooling means in said chamber outside of said furnace and adjacent said outlet thereof to' cool said band as it emerges from said furnace; and means inside said chamber for receiving said band asit emerges from said cooling means.

7. The apparatus of claim 6 wherein a condenser is positioned within said chamber adjacent to said furnace and wherein an opening is provided in One wall of said furnace to enable the volatilized constituent to come into contact with said condenser.

References Cited in the file of this patent OTHER REFERENCES Industrial Furnaces, vol. II, by-W. Trinks; Second I Edition,- 1944, published by John Wiley and- Sons, Inc.,

New York, N.Y., pp. 128-140; 

6. APPARATUS FOR TREATING A BAND OF METALLIC ALLOY AT LEAST ONE CONSTITUENT OF WHICH IS A VOLATIZABLE ELEMENT, SAID APPARATUS COMPRISING: A VACUUM CHAMBER; A FURNACE MOUNTED WITHIN SAID CHAMBER AND HAVING AN INLET AND AN OUTLET FORMED IN OPPOSED RELATION IN THE WALLS THEREOF; MEANS IN SAID CHAMBER FOR HOLDING SAID BAND, SAID BAND BEING FED THEREFROM THROUGH SAID FURNACE BETWEEN SAID INLET AND SAID OUTLET, SAID FURNACE BEING PROVIDED WITH HEATING MEANS TO RAISE THE TEMPERATURE OF SAID BAND ABOVE THE VOLATILIZATION TEMPERATURE OF SAID VAPORIZABLE ELEMENT TO EFFECT VOLATILIZATION THEREOF; MEANS COMMUNICATING WITH THE INTERIOR OF SAID FURNACE AT A POINT BETWEEN SAID INLET AND SAID OUTLET FOR REMOVING A PORTION OF THE VOLATILIZED ELEMENT THEREFROM; COOLING MEANS IN SAID CHAMBER OUTSIDE OF SAID FURNACE AND ADJACENT SAID OUTLET THEREOF TO COOL SAID BAND AS TI EMERGES FROM SAID FURNACE; AND MEANS INSIDE SAID CHAMBER FOR RECEIVING SAID BAND AS IT EMERGES FROM SAID COOLING MEANS. 